#define _CRT_SECURE_NO_WARNINGS 1 

#include<cstdio>
#include<algorithm>
#include<cstring>

using namespace std;

const int N = 6010;
int n;
int h[N], e[N], ne[N], idx;
int happy[N];
int f[N][2];
bool hus_fa[N];

void add(int a, int b)
{
	e[idx] = b; ne[idx] = h[a]; h[a] = idx++;
}

void dfs(int u)
{
	f[u][1] = happy[u];
	for (int i = h[u]; i != -1; i = ne[i])
	{
		int j = e[i];
		dfs(j);
		f[u][0] += max(f[j][0], f[j][1]);
		f[u][1] += f[j][0];
	}
}

int main()
{
	scanf("%d", &n);
	memset(h, -1 , sizeof h);
	for (int i = 1; i <= n; i++) scanf("%d", &happy[i]);
	for (int i = 0; i < n - 1; i++)
	{
		int a, b;
		scanf("%d%d", &a, &b);
		add(b, a);
		hus_fa[a] = true;
	}

	int root = 1;
	while (hus_fa[root]) root++;

	dfs(root);

	printf("%d\n", max(f[root][0], f[root][1]));
	return 0;
}